The present invention relates to a neuromodulation system for managing pain and/or various motor disorders. More specifically, the invention relates to a specially programmed computer system for use with known neuromodulation systems to assist in the performance of pre-, intra- and post-operative procedures relating to the determination and optimization of a patient's therapeutic regimen.
A neuromodulation system can deliver stimulation to tissue or nerve centers for the treatment of nervous or muscular disorders. One class of neuromodulation systems includes spinal cord stimulation (SCS) systems, which deliver a particularized electrical pulse to a specified region of a patient's spinal cord to effect the management of chronic or acute pain.
An SCS system includes a pulse generator, whether of a totally implanted or an RF-coupled nature, which delivers an electrical pulse through at least one multi-electrode lead positioned within the epidural space of a patient. It is the intention to position the lead so that the delivered electrical energy is directed to particular spinal nerve roots and/or nerve bundles associated with one or more pain-afflicted dermatomes. The delivered electrical pulse, practically, creates an analgesic effect, masking the pain sensed by the patient.
As the use of electrical energy for pain management or the treatment of motor disorders is an inexact science, an optimum therapeutic regimen must be determined. For any neuromodulation system utilizing an electrical pulse, this requires defining a pulse waveform (e.g., signal pulse width, frequency, phase and amplitude), as well as determining the proper multi-electrode lead position and electrode polarity configuration. Current SCS devices allow each of these parameters, excluding lead position, to be modified non-invasively.
A typical RF-coupled SCS system will include an implanted receiver that receives pulse information from an external transmitter. The external transmitter can be programmed with waveforms and treatment (dose) times. As mentioned above, the electrodes are arrayed on lead(s) which are electrically coupled to the receiver. Each electrode is capable of assuming a positive, negative or neutral polarity. One such system is described in detail in U.S. Pat. No. 4,612,934, the disclosure of which is incorporated herein by reference.
Current SCS systems may use one or two multi-electrode leads, with each lead possessing between four and eight electrodes positioned along the distal end of the lead. As the number of available electrodes increase, the possible number of electrode combinations (a "combination" including at least one cathode and anode), increases disproportionately. Accordingly, computer assistance in programming and assessing these electrode combinations and waveform variations would be beneficial. Specifically, computer programming and evaluation assistance would enable a reduction in the time needed by the patient and physician to optimize the therapeutic regimen.
The use of a computer interface to aid in selecting stimulation patterns is disclosed in U.S. Pat. No. 5,370,672. That system discloses a tablet and stylus input device used by the patient to draw a topographical sketch, relative to a human representation, of the pain being experienced. This sketch, or "pain map," is then compared for overlap with a sketch made of the patient's experienced or perceived area(s) of paresthesia ("paresthesia" meaning the perceived sensation produced by electrical stimulation of nerve roots and/or nerve bundles). The system of the '672 patent also allows the patient or physician to adjust the treatment regimen to attain better concordance between the areas of pain and areas of stimulation. Notwithstanding, the '672 patent does not include pre-operative or intra-operative features that can be instrumental to the success of achieving effective stimulation, whereas improper lead placement may prevent optimum or even adequate stimulation. Moreover, the '672 patent teaches the use of random presentation of electrode configurations to determine an optimum configuration. Although such method may avoid sampling bias, this unstructured and unfocused approach inherently requires the sampling of a large population to ensure that worthy data (i.e., that which is capable of leading to positive or effective stimulation) is obtained.
One object of this invention is to use a computer database of information in connection with the pain map of an individual patient to aid the physician in making more accurate decisions regarding waveform and electrode configuration definition as well as multi-electrode lead placement.
In addition, it would be very useful to have the ability to record and process patient responses to test stimulation patterns during the operation of placing the electrodes, so as to give the physician real-time information that can be used to effectively position the multi-electrode leads within the patient's body. Thus, another object of this invention is to use computing power to process patient responses to test stimulation patterns that are applied during the implantation procedure and provide the physician with information that can be used to make decisions regarding lead placement and stimulation settings.
Finally, another object of the present invention is to provide computer assisted post-operative presentation and assessment of stimulation settings, which utilizes, at least in one mode of operation, an iterative, systematic approach to determining one or more optimum stimulation settings.